In the hands of a skilled surgeon, surgical instruments may be used to repair or replace broken or damaged Joints and limbs. Typically, these instruments are specifically designed for particular surgical tasks to improve the quality of the result, as well as to make the surgeon's job easier and faster. These latter two attributes produce hidden advantages. Making the surgeon's job easier reduces the surgeon's fatigue thereby conserving the surgeon's strength and alertness to ensure optimum performance throughout the entirety of lengthy surgeries. Saving time is of importance in surgical endeavors because risk to the patient is reduced by shortening the surgery.
One of the tasks encountered by surgeons is temporarily fastening bones together with wire. Primarily, this task arises in two settings, one being a bone fracture wherein the fragments may be temporarily joined by looping a wire around the fragments and twisting the ends of the wire about one another thereby tightening the loop to fasten the fragments in place. The other setting occurs during implant surgery wherein the bones need reinforcement to prevent them from splintering during the insertion of the implants. This is accomplished in much the same way as when fastening the fragments; the wire is looped around the bone and drawn tight.
The ends of the wires are normally preformed into loops which can be hooked with the instruments to aid in manipulation. In any one operation, numerous wires may be used to securely fasten the bones and distribute the reinforcement over a larger area. Because so many wires must be so tightly wound, the task can become fatiguing. In addition, as each wire must be manipulated around the bone, the end of the wire is hidden from sight thereby increasing the tedium associated with the task.
Prior to the present invention, passing the wire under the bone and twisting the ends required at least two instruments. The first prior art instrument was shaped something like a bent crochet hook. The end of this instrument was inserted underneath and around the bone, one of the looped ends of the wire was placed in the notch near the tip of the hook and the instrument was withdrawn to pull the wire underneath the bone. Then, a second instrument having a hook and an offset rotating handle was used to tightly twist the wires by placing the looped ends of the wire over the hook and orbiting the handle about the hook to cause the ends of the wire to wrap around one another to form a wire twist. When the desired tightness was achieved, the hook was extracted from the wire loop ends and the process was repeated as necessary. Thus, two prior art instruments were required to perform the tasks.
In order to solve these and other problems in the prior art, the inventor has succeeded in designing and developing a single surgical instrument to both pass the wire under the bone and twist its ends. The instrument has a handle assembly mounted on a rod-like axle member with a C-shaped hook at the end opposite the handle assembly. The hook is bent so that it lies in a plane substantially perpendicular to the handle assembly for ergonomic reasons. Thus, when the user holds the handle, the hook is more visible, and the user's hand is comfortably positioned to apply relatively large loads to the hook during insertion and extraction. Unlike the prior art instrument, the new surgical instrument may be inserted and extracted by simply twisting the forearm. The prior art instrument required that the surgeon's hand move in a large arc about the patient's bone, a movement requiring greater effort and dexterity. Thus, the surgeon inserts the hook around the bone, places a looped end of the wire in a notch near the end of the hook and extracts the hook thereby pulling the wire around the bone. After the wire is pulled through, both ends of the wire are slipped around the hook and twisted by using the handle assembly. The handle assembly incorporates a crank with two handles separated by a grip so that the hook can be operated with two hands to quickly and tightly twist the wires about the bone. Unlike the prior art instrument, the hook of the new surgical instrument may easily be turned without swinging the wire ends significantly from side to side. Thus, lower cyclic loads are imparted on the bone and wire. The configuration of the handle assembly also allows the surgeon to apply tension to the wire as it is twisted so as to ensure that the wire is tightly twisted around the bone.